Trials Australia Forums

Turning my attention to my TY175 exhaust, I find that the gauze section of the removable baffle
has no wrapping, -ok, no probs, I have the correct fibreglass wrap material, I can do that easy. But the way it is I can't see that it would make much difference. (The zorst is fairly loud which I'm not mad about - I prefer stealth!)
The system as is seems to be pretty well 'straight through'. In other words the gasses would flow straight through the centre of the exhaust system, out of the baffle, without deviation. In most other 2-strokes I've seen the baffle re-routes exhaust gasses in some way to add quietness. Does this 'straight-through' thing seem right to you?
Am I missing a component that re-routes the exhaust gasses so as to make the baffle actually work as a silencer?
My removable baffle looks dead stock (not cut), the forward end of it is just an open-ended tube 30mm (very approx) diameter.

That is just standard mid 1970s Yamaha muffler design and yes they sound very raspy. The muffler would originally have had a little cast aluminium swirler fitted into the section of the muffler upstream of the baffle. That 30mm of straight pipe on the inlet of the baffle forms the carbon trap. The swirler caused any particles of (glowing) carbon to move outwards and get caught on the outside of that 30mm piece while the gases went through the 30mm piece. That's what the reduced diameter section of the muffler casing is for. It holds the swirler. The swirler probably makes it a bit quieter, but the first time someone burns out the carbon, the swirler usually melts and falls out
Aftermarket mufflers are quite popular on TY175s for a few reasons:
They improve the exhaust note greatly
The original muffler usually falls off when the mounting lug breaks off the frame and is often lost
They make it a lot quieter
They are lighter
WES end mufflers make them run better (and probably other brands do too, but I haven't tried them)

If you can get hold of the Yamaha muffler made for the TY175JC, you will achieve a wonderful level of stealth. They were made to meet the ADRs for noise which were very strict back then. Performance is very good too, but they are a bit heavier than the standard one

Ta David. I thought there must be something (swirly bit) missing, thanks for confirmation. Well anyway, in the meantime I can use earplugs (guaranteed to greatly improve engine condition when worn).
And yes, you picked it, - the muffler mounting lug has broken off the frame loop!

Just a 'Thank you' David for the exhaust heat shield. Nice straight unit, It fits perfectly, thanks mate.
(Isn't it funny how the lack of some minor components on a bike -as in this case - can make it look naked... sort of 'uneasy', whereas other things deleted can make a bike look better!)
The heatshield 'finishes it off' nicely. I'm about to give the little TY my first ride, (though at about 40c today, it's going to be a bit of a trial (sorry!), maybe 'll leave it 'til tomorrow!)
-Jools